1. Technical Field
The present invention relates generally to refractory materials. More particularly, the invention relates to a refractory material which is light in weight, has a high noise reduction capacity and a reduced Si02 content. Specifically, the present invention relates to such a refractory material which is used primarily in furnace liners, combustion chambers and baffles.
2. Background Information
Traditional refractory products made from alumina silicate (Al203-Si02) contain large amounts of silica (Si02), typically in the range of about 45 to 75 percent. These products are available in granular form or as man-made fibers for vacuum-forming. The fiber products are commercially available under the tradenames of—FiberfraX®, Kaowool®, Alcen®, Saffil® etc. In addition to these Al203-Si02 fiber products, there are newly invented “bio-soluble fiber products” available to meet recent European regulations. These products (tradenames—Isofrax®, Insulfrax®, Superwool-607®, Superwool-607 Max®, Superwool-607 HT®) are rich in alkaline earths such as magnesium oxide, calcium oxide and significant amounts of silica (typically 60-80%). These bio-soluble fiber products exhibit very high level of solubility in lung fluids which helps to reduce their toxicity on human body.
While these traditional products have been successful in many regards, they do have some drawbacks. For example, silica is problematic if fluxing elements from group 1 of the periodic table are present in the material, most typically sodium (Na) and potassium (K). When various solid fuels are burned in a combustion chamber lined with a refractory material having high silica content, the air to fuel ratio is difficult to control and is continuously changing. There are times when the air to fuel ratio falls below 1:1, at least part of the time. The air to fuel ratio of less than 1:1 is harmful to silica, causing the silica to undergo a reduction reaction which ultimately leads to failure of the refractory material. Thus there is a need within the art to produce a refractory material with satisfactory qualities while reducing the silica content.